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661.
Aquaculture ponds are dominant features of the landscape in the coastal zone of China.Generally,aquaculture ponds are drained during the non-culture period in winter.However,the effects of such drainage on the production and flux of greenhouse gases(GHGs)from aquaculture ponds are largely unknown.In the present study,field-based research was performed to compare the GHG fluxes between one drained pond(DP,with a water depth of 0.05 m)and one undrained pond(UDP,with a water depth of 1.16 m)during one winter in the Min River estuary of southeast China.Over the entire study period,the mean CO_2flux in the DP was(0.75±0.12)mmol/(m~2·hr),which was significantly higher than that in the UDP of(-0.49±0.09)mmol/(m~2·hr)(p0.01).This indicates that drainage drastically transforms aquaculture ponds from a net sink to a net source of CO_2in winter.Mean CH_4and N_2O emissions were significantly higher in the DP compared to those in the UDP(CH_4=(0.66±0.31)vs.(0.07±0.06)mmol/(m~2·hr)and N_2O=(19.54±2.08)vs.(0.01±0.04)μmol/(m~2·hr))(p0.01),suggesting that drainage would also significantly enhance CH_4and N_2O emissions.Changes in environmental variables(including sediment temperature,p H,salinity,redox status,and water depth)contributed significantly to the enhanced GHG emissions following pond drainage.Furthermore,analysis of the sustained-flux global warming and cooling potentials indicated that the combined global warming potentials of the GHG fluxes were significantly higher in the DP than in the UDP(p0.01),with values of739.18 and 26.46 mg CO_2-eq/(m~2·hr),respectively.Our findings suggested that drainage of aquaculture ponds can increase the emissions of potent GHGs from the coastal zone of China to the atmosphere during winter,further aggravating the problem of global warming. 相似文献
662.
在如今快速发展的新时代背景下,环境保护工作中如何更加快速的、有效的、准确的检测环境空气中总挥发性有机物(Total Volatile Organic Comp简称TVOC)是目前环境监测以及环境应急监测工作中的重点,光离子化法检测TVOC,以其灵敏度高,响应范围广,现场可得出结果等优势,成为光离子化法检测TVOC的非常值得推荐的一个检测方法,此文就光离子化总量测定法的相关依据、原理、技术指标、安全可靠性以及仪器的使用方法等方面进行了详细分析与探讨。 相似文献
663.
Lihong Zhang Shucheng Huang Kun Li Mujeeb Ur Rehman Xiong Jiang Xiaole Tong Hui Zhang Muhammad Kashif Iqbal Khalid Mehmood Suozhu Liu Yaoqin Shen Jiakui Li 《Food and environmental virology》2018,10(4):373-377
Hepatitis E is an important public health concern throughout the world. Many molecular and serological surveys have reported the prevalence and genotypic characteristics of HEV in humans and animals worldwide. However, the genotypic characterization of this virus is very limited in Tibetan pigs. Hence, we aimed to explore the genotype of HEV, prevailing among Tibetan pigs in China. For this purpose, 253 bile samples of Tibetan pigs (free-range animals) were collected from different slaughterhouses during 2017–2018 and subsequently tested for HEV RNA by RT-nPCR. A total of 11 out of 253 (4.35%) samples tested were positive for HEV RNA. Based on the sequence alignment and phylogenetic analysis, all the isolated HEV strains belonged to genotype 4 and clustered into subtype 4b by sharing more than 84.8–95.2% identities with other reported strains. Our results concluded that HEV genotype 4 is prevailing among Tibetan pigs in Tibet, China. 相似文献
664.
将冷阱用于液样浓缩器(LSC)/色谱/质谱(GC/MS)装置中,可对饮用水中挥发性有机污染物进行快速定性、定量分析.此方法适用于对饮用水及天然水体中挥发性有机污染物的普查和监测. 相似文献
665.
Chuanqi Li Qianqian Li Dongge Tong Qingliang Wang Mingge Wu Bohua Sun Guijin Su Li Tan 《环境科学学报(英文版)》2020,32(7):1-12
Volatile organic compounds (VOCs) are major contributors to air pollution.Based on the emission characteristics of 99 VOCs that daily measured at 10 am in winter from 15 December 2015 to 17 January 2016 and in summer from 21 July to 25 August 2016 in Beijing,the environmental impact and health risk of VOC were assessed.In the winter polluted days,the secondary organic aerosol formation potential (SOAP) of VOC (199.70±15.05 mg/m3) was significantly higher than that on other days.And ar... 相似文献
666.
Spatiotemporal variations of nitrate sources and dynamics in a typical agricultural riverine system under monsoon climate 总被引:1,自引:0,他引:1
Hao Jiang Wenjing Liu Jiangyi Zhang Li Zhou Xiaode Zhou Ke Pan Tong Zhao Yuchen Wang Zhifang Xu 《环境科学学报(英文版)》2020,32(7):98-108
Nitrogen pollution is a serious environmental issue in the Danjiangkou Reservoir region(DRR),the water source of the South-to-North Water Diversion Project of China.In this research,seasonal surveys and a bi-weekly time series survey were conducted in the Qihe River Basin,one of the most densely populated agricultural basins in the DRR.Hydrochemical compositions (NO3Cl),dual isotopes (δD-H2O,δ18O-H2O,δ15N-NO3-,and δ 相似文献
667.
668.
通过定期监测北京市某城市污水再生处理过程各单元出水中的隐孢子虫和贾第鞭毛虫(两虫)浓度,系统考察了污水再生处理系统对两虫的去除特性.结果表明,原污水、初沉池出水、二沉池出水、絮凝沉淀池出水和砂滤池出水中隐孢子虫的平均检出量分别为238、179、6、1、0.3个·L-1,贾第鞭毛虫的平均检出量分别为1 568、1048、22、4、0.6个·L-1.污水再生处理系统对隐孢子虫和贾第鞭毛虫的总去除率分别为2.98log(99.895%)和3.46log(99.965%).一级处理工艺对污水中两虫的去除效果并不理想,去除率分别只有0.13log和0.18log.二级生物处理对两虫的去除贡献最大,去除率分别达1.50log和1.67log.污水深度处理工艺(絮凝-沉淀-砂滤)能有效提高两虫的去除效果.污水厂进水中的两虫检出量随季节变化,雨季较低,旱季较高. 相似文献
669.
La2O3/ZnO/TiO2光催化降解活性艳红K-2BP的研究 总被引:1,自引:0,他引:1
采用溶胶-凝胶法制备了La2O3/ZnO/TiO2复合光催化剂,以紫外灯为光源,活性艳红K-2BP为模型降解物,研究了La2O3/ZnO/TiO2的光催化性能。结果表明:当锌和镧的掺杂量w(ZnO)=20%, w(La2O3)=0.5%, 煅烧温度为500℃时,La2O3/ZnO/TiO2复合光催化剂的光催化活性最高;当催化剂投加量4 g/L,通气量800 mL/min,初始pH值3.12时,La2O3/ZnO/TiO2对活性艳红K-2BP的降解效果最好。实验证明,La2O3/ZnO/TiO2对活性艳红K-2BP的降解遵从Langmuir-Hinshelwood动力学模型,测得其反应速率常数k=11.5 mg/(L·min);吸附常数K=2.88×10-2 L/mg。 相似文献
670.